Method for handling failure of handover procedure in wireless communication system and apparatus therefor

Abstract

A method handling a link failure by a user equipment (UE) in a wireless communication system is disclosed. The method includes steps of suspending at least one data radio bearer (DRB) upon detecting an occurrence of the link failure; transmitting, to a specific cell, a radio resource control message indicating the occurrence of the link failure; receiving a response message as a response of the radio resource control message from the specific cell; and resuming the at least one suspended DRB.

The invention claimed is: 
     
       1. A method for handling a link failure by a user equipment (UE) in a wireless communication system, the method comprising:
 detecting an occurrence of the link failure; 
 transmitting, to a specific cell, a radio resource control (RRC) connection re-establishment request message with maintaining configuration for at least one data radio bearer (DRB) configured in a serving cell; 
 receiving a response message as a response of the RRC connection re-establishment request message from the specific cell, wherein the response message includes an indicator indicating whether to release the configuration for the at least one DRB configured in the serving cell or not; and 
 communicating a signal via the at least one DRB to the specific cell when the indicator indicates not to release the configuration for the at least one DRB configured in the serving cell. 
 
     
     
       2. The method of  claim 1 , wherein the link failure comprises a failure of a handover procedure and the specific cell is a source cell of the handover procedure. 
     
     
       3. The method of  claim 1 , wherein the link failure comprises a radio link failure (RLF) and the specific cell is a selected cell during cell selection procedure after the RLF. 
     
     
       4. The method of  claim 1 , wherein the response message comprises a RRC connection re-establishment message. 
     
     
       5. A user equipment (UE) in a wireless communication system, the UE comprising:
 a radio frequency (RF) unit; and 
 a processor connected with the RF unit and configured to: 
 detect an occurrence of a link failure; 
 transmit a radio resource control (RRC) connection re-establishment request message to a specific cell with maintaining configuration for at least one data radio bearer (DRB) configured in a serving cell; 
 receive a response message as a response of the RRC connection re-establishment request message from the specific cell, wherein the response message includes an indicator indicating whether to release the configuration for the at least one DRB configured in the serving cell or not; and 
 communicate a signal via the at least one DRB to the specific cell when the indicator indicates not to release the configuration for the at least one DRB configured in the serving cell. 
 
     
     
       6. The UE of  claim 5 , wherein the link failure comprises a failure of a handover procedure and the specific cell is a source cell of the handover procedure. 
     
     
       7. The UE of  claim 5 , wherein the link failure comprises a radio link failure (RLF) and the specific cell is a selected cell during cell selection procedure after the RLF. 
     
     
       8. The UE of  claim 5 , wherein the response message comprises a RRC connection re-establishment message.